In a CATV (Cable TV) system, the outer conductor of the coaxial cable is electrically bonded to earth ground, i.e., grounded, at every end-user's home. This grounding is typically accomplished using a device called a bonding block or ground block. This device is usually located outside the home near the electrical service entry. Bonding is achieved by attaching the coaxial cable to the bonding block and attaching a wire from the electrical service ground to the bonding block. Because residential bonding blocks are usually outside the home, they are exposed to the elements such as rain, salt, sunlight, temperature extremes, and other harsh conditions. Since bonding blocks are primarily used as safety devices, it is imperative that they maintain a quality bond between the outer conductor of the coaxial cable and earth ground under these conditions.
Most existing ground blocks are made of inferior materials such as aluminum or zinc and corrode very quickly. Some are made of stainless steel but are constructed in such a way as to allow moisture to penetrate the interface between the coaxial cable and the bonding block, thus degrading the television signal and causing corrosion at the interface unless a weather seal is used.